Prospective, Randomized-control Trial Comparing Standard Intramedullary Tibial Fixation With Micromotion Tibial Intramedullary Fixation

The advent of the intramedullary nail (IMN) has revolutionized the treatment of tibial shaft fractures due to its percutaneous route of insertion, frequent facilitation of immediate weightbearing, and high rate of union. Recent research has revealed that selection of an appropriate IMN diameter is vital for maintaining fracture reduction and preventing complications. Using a larger diameter nail increases construct stability, permits load-sharing, and may lead to higher rates of union. On the other hand, aggressive reaming to permit a larger nail diameter can result in iatrogenic fracture upon insertion or removal.

Modern tibial nail designs have remained largely unchanged in the last 20 years with small ergonomic and efficiency changes without large scale improvements in their biomechanical induction of bone healing at the fracture site. Traditionally they include distal locking screws as well as proximal locking screws that are either fixed or dynamic allowing for small but largely irrelevant amounts of motion. Our understanding of bone healing and indirect bone generation includes the concept of micromotion which induces the creation of fibrous followed by bony callus. This concept requires strain levels and adequate micromotion at fracture sites to be biomechanically advantageous. One new tibial nail device recently available in the US and FDA approved for tibial nail fixation hopes to improve the biomechanical and biology environment for tibial healing, the OrthoXel tibial nail system. Unfortunately, there is a paucity of strong clinical data to support it. Additionally, there have been no prospective, randomized studies investigating the used of this nail compared to standard tibial nail designs and no studies have evaluated it in high risk tibial non-union patients..

The primary purpose of this study is to perform a high-quality randomized control trial comparing intramedullary tibial nail fixation with standard design nails compared to a micromotion tibial nail device to evaluate the rates of union and post-operative outcomes. In an evaluation of patient factors, fracture patterns and patient reported outcomes, the investigators will bring clarity to the question of indications for the micromotion tibial nail in standard and high risk patients. To characterize our patient population, the investigators will evaluate type of injury (closed, open, gunshot wound), fracture morphology (OTA classification), patient risk factors (age, isolated vs. poly-trauma, Comorbidities, smoking, and Vit D levels) and surgical outcomes (blood loss, surgical time, construct stability). In addition to objective radiographic, ultrasonographic and physical exam outcomes, the investigators will collect patient reported outcomes in the form of PROMIS CAT and VAS scores.

Given the existing limitations in the literature, there is no guidance on indications for use of micromotion tibial nail fixation (MMIMNF) compared to standard intramedullary nail fixation (IMNF). By taking an approach that will be prospective and randomized, while assessing all known risk factors, the investigators expect our results will guide surgical treatment decisions around the use of these devices and in which populations they may be most useful. .

The proposed trial will be a parallel-group, superiority trial with equal randomization enrolling 242 tibial nail patients. Patients will be categorized into 2 cohorts: IMNF fixation(cohort 1), and MicroMotion Intramedullary tibial Nail fixation (cohort 2). The primary outcome will be nonunion. Secondary outcomes will include: overall complications (as a composite result (Infection ((deep and superficial)), revision surgery rate, removal of metalwork, non-union, malunion, amputation and death). Patient-Reported Outcomes Measurement Information System Physical Function Computerized Adaptive Testing (PROMIS PT CAT) scores, range of motion (ROM), pain, radiographic outcomes, time to bridging callus based on mRUST (>11) on Xray, time to single leg stance, and degree of callus seen on ultrasound at 6 & 12 weeks.